/*
 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
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 *
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 *
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 */
package javax.swing.event;

import javax.swing.RowSorter;

/**
 * <code>RowSorterEvent</code> provides notification of changes to
 * a <code>RowSorter</code>.  Two types of notification are possible:
 * <ul>
 * <li><code>Type.SORT_ORDER_CHANGED</code>: indicates the sort order has
 * changed.  This is typically followed by a notification of:
 * <li><code>Type.SORTED</code>: indicates the contents of the model have
 * been transformed in some way.  For example, the contents may have
 * been sorted or filtered.
 * </ul>
 *
 * @see javax.swing.RowSorter
 * @since 1.6
 */
public class RowSorterEvent extends java.util.EventObject {

  private Type type;
  private int[] oldViewToModel;

  /**
   * Enumeration of the types of <code>RowSorterEvent</code>s.
   *
   * @since 1.6
   */
  public enum Type {
    /**
     * Indicates the sort order has changed.
     */
    SORT_ORDER_CHANGED,

    /**
     * Indicates the contents have been newly sorted or
     * transformed in some way.
     */
    SORTED
  }

  /**
   * Creates a <code>RowSorterEvent</code> of type
   * <code>SORT_ORDER_CHANGED</code>.
   *
   * @param source the source of the change
   * @throws IllegalArgumentException if <code>source</code> is <code>null</code>
   */
  public RowSorterEvent(RowSorter source) {
    this(source, Type.SORT_ORDER_CHANGED, null);
  }

  /**
   * Creates a <code>RowSorterEvent</code>.
   *
   * @param source the source of the change
   * @param type the type of event
   * @param previousRowIndexToModel the mapping from model indices to view indices prior to the
   * sort, may be <code>null</code>
   * @throws IllegalArgumentException if source or <code>type</code> is <code>null</code>
   */
  public RowSorterEvent(RowSorter source, Type type,
      int[] previousRowIndexToModel) {
    super(source);
    if (type == null) {
      throw new IllegalArgumentException("type must be non-null");
    }
    this.type = type;
    this.oldViewToModel = previousRowIndexToModel;
  }

  /**
   * Returns the source of the event as a <code>RowSorter</code>.
   *
   * @return the source of the event as a <code>RowSorter</code>
   */
  public RowSorter getSource() {
    return (RowSorter) super.getSource();
  }

  /**
   * Returns the type of event.
   *
   * @return the type of event
   */
  public Type getType() {
    return type;
  }

  /**
   * Returns the location of <code>index</code> in terms of the
   * model prior to the sort.  This method is only useful for events
   * of type <code>SORTED</code>.  This method will return -1 if the
   * index is not valid, or the locations prior to the sort have not
   * been provided.
   *
   * @param index the index in terms of the view
   * @return the index in terms of the model prior to the sort, or -1 if the location is not valid
   * or the mapping was not provided.
   */
  public int convertPreviousRowIndexToModel(int index) {
    if (oldViewToModel != null && index >= 0 &&
        index < oldViewToModel.length) {
      return oldViewToModel[index];
    }
    return -1;
  }

  /**
   * Returns the number of rows before the sort.  This method is only
   * useful for events of type <code>SORTED</code> and if the
   * last locations have not been provided will return 0.
   *
   * @return the number of rows in terms of the view prior to the sort
   */
  public int getPreviousRowCount() {
    return (oldViewToModel == null) ? 0 : oldViewToModel.length;
  }
}
